1. Field of the Invention
The present invention generally relates to electronic apparatuses, power control apparatuses and methods for controlling a supply of power, and more particularly to an electronic apparatus, a power control apparatus and a method for controlling a supply of power in that desired functions can be realized by using a connector device corresponding to a function device connected to an detachable function device.
Recently, a laptop personal computer using a battery is provided. In such a laptop personal computer, just the most essential functions are provided in its base unit to minimize the base units. Accordingly, a PC card slot is provided in the base unit to extend their functions. A desired function is realized by mounting a PC card, which has a needed extended function, to the PC card slot.
2. Description of the Related Art
A conventional portable or laptop personal computer will be described by referring to FIG. 1.
FIG. 1 is a block diagram showing a construction of the conventional laptop personal computer.
The conventional laptop personal computer 1 includes an information processing system 2, a battery unit 3, a power source circuit 4, a PC card slot 5 and a drive bay 6.
The information processing system 2 includes a CPU 7, bridge circuits 8 and 9, a graphic controller VGA 10, an audio controller 11, a PC card controller 12, a hard disk drive 13 and a floppy disk drive 14.
The CPU 7 processes information in accordance with programs. The bridge circuit 8 is provided between the CPU 7 and each part and controls a connection between the CPU 7 and each part.
The bridge circuit 9 is provided between the drive bay 6 and a bus 22 and controls a connection between the drive bay 6 and the bus 22. The graphic controller VGA 10 controls for displaying processed data.
The audio controller 11 processes audio data. The PC card controller 12 is provided between the PC card slot 5 and the bus 22 and controls a connection between the PC card slot 5 and the bus 22.
The battery unit 3 generates power. Voltage generated by the battery unit 3 is supplied to the power source circuit 4. The power source circuit 4 supplies power to a drive unit mounted to the drive bay 6 and a PC card inserted into the PC card slot 5.
A drive unit, such as a CD-ROM drive unit, a DVD-ROM drive unit, a hard disk drive unit or a magneto-optical disc drive unit, is mounted to the drive bay 6. A PC card, such as a modem card, an IC memory card, a SCSI card or a DVD decoding card, is inserted into the PC card slot 5.
A case of mounting the DVD-ROM drive unit to the drive bay 6 will now be described.
As shown in FIG. 1, the DVD-ROM drive unit 15 is mounted to the drive bay 6 in order to read data from a DVD-ROM disk 16. However, the CPU 7 can not process signals read by the DVD-ROM disk unit 15 because the data from the DVD-ROM drive unit 15 is encoded. Accordingly, in a system shown in FIG. 1, a DVD decoding card 17 is inserted into the PC card slot 5 to decode the data read by the DVD-ROM disk unit 15. The signals are converted to data that can be processed by the CPU 7 so as to be displayed.
The DVD decoding card 17 includes a decoder 18 and a processing circuit 19. The decoder 18 decodes data read by the DVD-ROM drive unit 15. The processing circuit 19 controls the data to decode at the decoder 18.
The DVD decoding card 17 is capable of connecting to an exclusive cable 20 for a television. Images and audio are output to a television receiver 21 via the exclusive cable 20.
In the conventional laptop personal computer shown in FIG. 1, when the PC card is inserted into the PC card slot 5, the power source circuit 4 always supplies power to the PC card slot 5, regardless of use or not use. For example, when the DVD decoding card 17 is inserted into the PC card slot 5, power is always supplied to the DVD decoding card 17 even if the DVD-ROM drive unit 15 is not connected to the drive bay 6. As a result, the battery unit 3 consumes extra power. In a state in which the DVD decoding card 17 is not used to decode data from the DVD-ROM disk 16, the power supplied to the DVD decoding card 17 is completely wasted.